1. Field of the Invention
The present invention relates to fuel vapor processing apparatus, which can temporarily adsorb fuel vapor and can purge the adsorbed fuel vapor to the engine—when needed. The fuel vapor is contained in a fuel vapor containing gas produced within a fuel tank for an internal combustion engine.
2. Description of the Related Art
A known fuel vapor processing apparatus (also called a canister) has a container filled with granular adsorption material (i.e. activated carbon) for adsorbing and desorbing the vapor contained in the fuel vapor containing gas. A pair of electrodes is positioned on opposite sides of the granular adsorption material (hereinafter simply called “absorption material”). When an electric current is applied for conduction between the electrodes, the adsorption material produces heat that enhances desorption of the vapor (see Japanese Laid-Open Patent Publication No. 6-280694).
Another type of known fuel vapor processing apparatus as disclosed in Japanese Laid-Open Patent Publication No. 2002-266709 has a container in which a cylindrical adsorption member is positioned. The adsorption member can adsorb and desorb the fuel vapor contained in a fuel vapor containing gas and has a honeycomb structure with a plurality of gas passable bores through which fuel vapor containing gas can flow.
With the apparatus of Japanese Laid-Open Patent Publication No. 6-280694, although the adsorption material can produce heat, the adsorption material does not have a honeycomb structure and cannot produce heat. With the apparatus of Japanese Laid-Open Patent Publication No. 2002-266709, although the adsorption member having the honeycomb structure is positioned within the container, the adsorption member cannot produce heat and thus, the desorption of the vapor cannot be enhanced
Therefore, there is a need of fuel vapor processing apparatus that has an adsorption member that can be substantially uniformly heated when an electric current is applied between a pair of electrodes.
One aspect according to the present invention includes a fuel vapor processing apparatus that has a container and an adsorption member positioned within the container. The adsorption member can adsorb a fuel vapor as a gas containing the fuel vapor flows through the adsorption member. A first electrode and a second electrode are attached to the adsorption member, so that the adsorption member can produce heat as a voltage is applied between the first and second electrodes across the adsorption member. The first and seconds electrodes are spaced from each other in a direction substantially parallel to the direction of flow of the gas through the adsorption member.